Examined Japanese Patent Publication SHO 50-32009 discloses a method of projecting images on a multiplicity of display units. This method employs an enlarging device for enlarging one image source to project images on a large screen provided by the multiplicity of display units.
The enlarging device comprises, for example, frame memories corresponding in number to the number of display units, and reading of data from the frame memories is controlled to obtain images at a desired enlargement ratio.
A multiscreen projector apparatus is also known which comprises a plurality of liquid crystal projectors providing a large screen as seen in FIGS. 8 and 9.
The projector apparatus comprises a plurality of rectangular parallelepipedal cabinets 7 joined together as arranged vertically and laterally on a base 8 and each having a liquid crystal projector 10 accommodated therein. In front of the projector 10, a screen 3 comprising a lenticular lens of the transmission type is fixed to a front opening portion of the cabinet 7 for projecting images thereon.
The image is projected on the screen 3 by each liquid crystal projector 10 through a projection lens 11, and the images on the plurality of screens 3 are combined into a large continuous image.
The projector apparatus has the problem that when the projection lens 11 has a large focal length, the depthwise dimension D of the cabinet 7 increases with the focal length to make the apparatus large.
This problem will be overcome by using a wide-angle lens of short focal length, but the projector then has the drawback of insufficient quantity of light at the peripheral portion of the screen.
The depthwise dimension of the cabinet can be decreased alternatively by using a plurality of mirrors for reflecting the light from the projector unit as in the liquid display device disclosed in Unexamined Japanese Utility Model Publication HEI 1-115778.
The liquid crystal display device has a rectangular parallelepipedal cabinet the interior space of which is divided into upper and lower spaces. The upper space provides a projection chamber corresponding to a screen in vertical dimension, and the lower space provides a chamber accommodating a projector therein. Accordingly, the front side of the projector accommodating chamber is a non-screen area, and it is impossible to provide the screen over the entire area of the cabinet front side.
Consequently, in the case where such liquid crystal display devices are assembled into a multiscreen projector apparatus, the single image forming area to be provided by the screens is divided by the non-screen areas and can not be one continuous image forming area.